Serial data isolator industrial control system providing intrinsically safe operation

A method of operating an industrial controller in a hazardous environment, the industrial controller comprising an intrinsically safe unit having reduced power levels unlikely to produce a spark sufficient to ignite a flammable atmosphere and a non-intrinsically safe unit not having reduced power levels, the intrinsically safe unit connected to a plurality of control points of an industrial process located in a hazardous environment, the method comprising the steps of:

• (a) placing the intrinsically safe unit in the hazardous area;
• (b) collecting data of the plurality of control points with the intrinsically safe unit in a serial format for transmission on an electrical conductor to the non-intrinsically safe unit;
• (c) limiting the transmission of power of the electrical signals on the electrical conductor to avoid the generation of sparks with sufficient energy to ignite a flammable atmosphere during a fault condition of the conductor;
• and
• (d) transmitting isolated electrical signals to the non-intrinsically isolated unit positioned outside the hazardous area.

A method of operating an industrial controller in a hazardous environment, the industrial controller comprising an intrinsically safe unit having reduced power levels unlikely to produce a spark sufficient to ignite a flammable atmosphere and a non-intrinsically safe unit not having reduced power levels, the intrinsically safe unit connected to a plurality of control points of an industrial process located in a hazardous environment, the method comprising the steps of:

• (a) placing the intrinsically safe unit in the hazardous area;
• (b) transmitting isolated electrical signals from the non-intrinsically isolated unit located outside the hazardous area to the intrinsically safe unit via an electrical conductor;
• (c) limiting the transmission of power of the electrical signals on the electrical conductor to avoid the generation of sparks with sufficient energy to ignite a flammable atmosphere during a fault condition of the conductor;
• and
• (d) receiving the power limited serial transmission at the intrinsically isolated unit and extracting data values therefrom to provide to the plurality of control points.